Density dependence of microwave induced magneto-resistance oscillations in a two-dimensional electron gas

TL;DR

This study investigates microwave-induced magneto-resistance oscillations in a 2D electron gas, revealing B-periodic oscillations with a density-dependent plateau and phase shifts, advancing understanding of edge-magneto-plasmons.

Contribution

It demonstrates the non-linear density dependence of B-periodic oscillations and identifies a plateau region with phase shifts, providing new insights into edge-magneto-plasmon behavior.

Findings

B-periodic oscillations are observed across various densities and mobilities.

The B-periodicity exhibits a plateau between 2.4 and 3 x 10^{11} cm^{-2}.

The phase of oscillations shifts continuously by two periods in the plateau region.

Abstract

We have measured the magneto-resistance of a two-dimensional electron gas (2DEG) under continuous microwave irradiation as a function of electron density and mobility tuned with a metallic top-gate. In the entire range of density and mobility we have investigated, we observe microwave induced oscillations of large amplitude that are B-periodic. These B-periodic oscillations are reminiscent of the ones reported by Kukushkin \textit{et al}[1] and which were attributed to the presence of edge-magneto-plasmons. We have found that the B-periodicity does not increase linearly with the density in our sample but shows a plateau in the range (2.4-3) 10^{11}\rm cm^{-2} $. In this regime, the phase of the B-periodic oscillations is found to shift continuously by two periods.